Construct - Issue 41

Project

CULVERT RECOVERY

INNOVATIVE TECHNIQUES ANDMATERIALSHAVE SAVEDADAMAGEDWATER STRUCTURE FROMCOLLAPSE INSOUTHWEST LONDON

The water and drainage management (WDM) division recently carried out a survey and repair to a damaged culvert that would have presented a significant health and safety risk if it had been left unattended. The concrete culvert, at Liberty Avenue in south west London, passes under the residential street in two locations and also encroaches under an adjacent A-road. FM Conway’s client, the London Borough of Merton, knew that there were some structural defects in the culvert, and asked the WDM team to carry out a survey of the area to identify the full scope of work required to make it safe. When the team arrived, they found that the crown of the pipe had collapsed in places, leaving reinforcement bars exposed, as well as damage caused by tree roots. There were also a number of connections intruding into the main pipe. After completing the survey, FM Conway’s team recommended a variety of different repair techniques that would meet all the

structural requirements and accommodate changes in shape and diameter within the culvert, allowing Merton to choose the best options to meet the budget. To avoid extensive excavation, Merton chose to focus on the installation of internal structural repairs to four sections where the culvert passed completely or partially under the carriageway. These included a bespoke GRP structural lining that provides full structural rehabilitation with an expected service life of over 100 years. In other areas, the WDM team installed UV- cured GRP liners to create a pipe of single internal diameter within the culvert’s different shapes, then filled the surrounding space with grout to provide additional structural integrity. The use of these bespoke, innovative solutions ensured that FM Conway delivered a cost-effective approach while maximising the repairs that could be done within the budget. The team also minimised disruption to local residents and traffic by using “no- dig” techniques for all the work.

LOCATION

Merton

A24

A236

LIBERTY AVENUE

9

9